The polyesters according to this invention are prepared from ether-containing dicarboxylic acids and ether-containing glycols. These polyesters have low permeability to oxygen and carbon dioxide and are useful in molded and extruded objects such as bottles and film for packaging food and beverages. They can also be used as gas barrier layers in multilayer film or sheet that can be prepared by one of several techniques such as coextrusion or lamination.
U.S. Pat. Nos. 3,408,334 and 3,522,328 describe polyamides prepared from p-phenylenedioxydiacetic acid. Makromolecular Chem., 32, 1 (1959) also describes this acid. U.S. Pat. Nos. 2,973,339, 3,558,557, 4,188,353, 4,384,106, and 4,398,017 disclose polyesters prepared using hetero-atom-containing diols but not hetero-atom-containing dicarboxylic acids.